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A 15-year-old boy was arrested for allegedly making threats of a "huge" shooting in the Santa Clarita Valley on Instagram. Kate Larsen reports from Santa Clarita for the NBC4 News at 11 on Sunday, Aug. 17, 2014. (Published Monday, Aug. 18, 2014)

Authorities on Sunday arrested a 15-year-old boy in connection with threats posted to Instagram warning people living in the Santa Clarita Valley that there will be a “huge" shooting soon.

A search warrant was executed at a home less than 24 hours after the threats were made and investigators said no firearms were found there.

The teen, who is a student at a school in the Santa Clarita area, "acted alone and no actual plan to assault any students or school had been formulated," according to Lt. Brenda Cambra of the Los Angeles County Sheriff's Department.

"Based on statements made by the suspect, it appears he made these posts to get a reaction from friends on social media, realizing too late that the threats were being taken seriously," Cambra said.

The first of about 100 calls from concerned parents regarding the photos was reported to deputies around 10 p.m. Saturday. The posts included stock photos of guns, dead bodies and a school marquee.

“We are aiming our guns mostly at high school students,” read one caption. “Be ready because blood will be shed and families will suffer. No mercy will be shown. Slow and painful deaths will happen on a very dreadful day.”

“I must not tell you which day it will be, you will find out yourself,” the post continued.

Other threats contained within the posts were said to be sexist and racist, officials said. The Instagram account has since been deleted.

“I was kind of shocked, I was alarmed,” said student Antonio Curiel, a friend of the teen.

Investigators said there is no evidence that the person posting the photos has access to the guns. A photo bearing the school marquee for Valencia High School turned out to be of another school in another state, officials said.

The William S. Hart Union High School District -- which began classes on Thursday -- released a statement regarding the threats Sunday morning.

"This morning, we became aware of a threat that was posted on social media made against our high schools. We take threats of this nature very seriously and we are working closely with the LA County Sheriff’s Department," said Superintendent Rob Challinor. "Extra precautions will be taken to ensure the safety of our students and staff on all of our campuses, while this is being investigated. We are looking forward to a day of student learning tomorrow, as we begin the first full week of the new school year."

The case is currently under investigation and anyone with information is asked to call the Santa Clarita Valley Sheriff’s Station at 661-255-1121.

The Instagram threat comes one month after social media accounts encouraged followers to send nude photos of teenagers in the Santa Clarita Valley. Officials could not say whether they were investigating the two incidents as being related.

"They should be safe and as parents we should be parenting our kids that if you're angry or kind of what are the boundaries of pranks," said parent Lori Scott.